Foam generating nozzle

ABSTRACT

A nozzle and method for generating a foamed liquid includes a nozzle body, a plurality of spaced orifices forming discrete jets of a liquid foam producing agent in an elongate passage in the nozzle body, and a solid surface defined in the body upon which the jets impinge. Gas inlet openings introduce gas into the passage and the gas and liquid foam producing agent are intimately mixed by deflection of the latter from the solid surface to produce foam in the passage.

United States Patent Conrad et al.

[ Sept. 17, 1974 I FOAM GENERATING NOZZLE [75] Inventors: Sherman E.Conrad; Dennis W.

Bintner, both of Des Moines, Iowa [73] Assignee: Delavan ManufacturingCompany,

West Des Moines, Iowa [22] Filed: Oct. 10, 1972 [21] Appl. No: 296,352

[52] U.S. Cl 239/8, 169/15, 239/428.5, 239/431, 239/432, 239/597 [51]Int. Cl B05b 7/04, B05b 15/04 [58] Field of Search 169/15; 239/8-10,428.5, 431, 432, 597, 598

[56] References Cited UNITED STATES PATENTS 1,753,443 4/1930 Murray239/597 2,127,883 8/1938 Norton 239/597 X 2,198,585 4/1940 Urquhart etal. 169/15 X 2,423,618 7/1947 Rotzer 169/15 X 2,492,037 12/1949 Freemanet al 169/15 X 2,761,516 9/1956 Vassilkovsky 169/15 2,765,856 l0/l956Schultz 169/15 3,199,790 8/1965 Giesemann 169/15 X 3,563,461 2/1971 Coleet al. 239/9 3,604,509 9/1971 Sachnik 169/15 3,701,482 10/1972 Sachnik169/15 FOREIGN PATENTS OR APPLICATIONS 221,878 6/1959 Australia 239/42851,166,068 10/1969 Great Britain 239/428.5 1,178,631 l/l970 Great Britain239/597 Primary ExaminerRobert S. Ward, Jr. Attorney, Agent, orFirm-Molinare, Allegretti, Newitt & Witcoff [5 7 ABSTRACT 20 Claims, 5Drawing Figures 1 FOAM GENERATING NOZZLE BACKGROUND AND SUMMARY OF THEINVENTION The present invention relates to foam generating nozzles and,more particularly, to a foam generating nozzle and method in which aliquid foaming agent impinges on a solid surface prior to the dischargeof the foam from the nozzle.

Foaming of liquid solutions is presently receiving wide attention todayin several fields. In the agricultural field, foam application isextremely attractive for the application of pesticides, including bothherbicides and insecticides. The foaming of pesticides substantiallyreduces both ground or aerial drift and thereby also reduces oreliminates altogether undesirable damage to surrounding crops andvegetation. In addition, the foam application of pesticides reducesrun-off which might otherwise result in environmental damage,

reduces evaporation, provide 5a ready visual indication of spraycoverage and reduces the amount of active chemicals that must be appliedper unit area. Foam application techniques are also enjoying wideattention in other agricultural fields including the protection ofplants against climatic conditions such as frost, hybridizing, seedingand the like. In addition to agricultural uses, foaming has been widelyused in other fields for several years including fire fighting anddetergent cleaning operations in which foam is employed as the cleaningagent.

In general two different methods have been employed in the generation ofsuch foams. In one method, a chemical foaming agent is added to thesolution to be sprayed which upon discharge from the applicatorchemically produces the desired foam. The second general method consistsof introducing air into a liquid to form millions of bubbles which makeup the foam. Such air can be introduced either by an air aspiratingnozzle in which the foam is formed just before being discharged from thenozzle or by the use of specially constructed foam generators and pumpswhich take in air and blend it with a small amount of foamable liquidand this foam is then pumped through a hose to the point of application.

The present invention is directed to a foam generating nozzle and methodin which air is introduced into a liquid foaming agent to generate thefoam just before discharge from the nozzle. Such foam generating nozzleshave taken several forms in. the past. In one form of foam generatingnozzle, the liquid foam producing agent is jetted onto a mesh strainer.The liquid passing through the strainer mesh reduces the pressure in thenozzle body to cause air to be drawn through the mesh and mixed with theliquid to generate foam. Another form of foam generating nozzle in usetoday comprises a simple elongate nozzle body through which the liquidfoam producing agent is jetted directly through the nozzle body withoutfurther contact with the nozzle. This jet of liquid foam producing agentreduces the pressure in the nozzle body to aspirate air into the bodywhere it is mixed with the liquid to form the foam which is dischargedfrom the nozzle.

In the present invention a foam generating nozzle and method of foamingproduces a high quality foam having millions of tiny air bubblesinterspersed in the foam. In the present invention at least one discretejet of liquid foam producing agent is formed in the nozzle body and asolid impingement surface is loacted in the path of the jet such thatthe jet impinges upon the surface and is deflected from the surface. Thedeflected liquid foam producing agent is thereby intimately mixed withthe air which has been drawn into the nozzle body to produce highquality foam which is discharged from the nozzle. The foam generatingnozzle of the present invention is simple in construction and,accordingly, the expense of manufacture is substantially reduced, aswell as the likelihood of failure during use from clogging, wear and thelike.

In one principal aspect, the present invention comprises a foamgenerating nozzle including a nozzle body and a passage extendingthrough the major part of the body. Orifice means is located adjacentone end of the body to form at least one discrete jet of liquid foamproducing agent in the passage along the axis of the orifice means andgas is introduced into the passage through gas inlet means on the nozzlebody. The jet of liquid foam producing agent is impinged upon a solidimpingement surface in the passage upstream of the discharge end of thebody in the path of the jet and on the axis of the orifice meansdeflecting the jet toward the axis of the passage to effect intimatemixing of the liquid foam producing agent and the gas to generate foamin the passage.

In another principal aspect, the present invention comprises a method ofgenerating foam including forming at least one discrete jet of a liquidfoam producing agent in a passage along an axial path, impinging the jetupon a solid surface in the axial path of the jet in the passage,introducing a gas into the passage, and intimately mixing the gas andliquid foam producing agent deflected from the solid surface to generatefoam in the passage, and discharging the foam from the passage.

These and other objects, features and advantages of the presentinvention will become evident upon consideration of the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWING In the course of this description,reference will frequently be made to the attached drawing in which:

FIG. 1 is a cross sectioned side elevation view of a preferredembodiment of foam generating nozzle constructed and which operates inaccordance with the principles of the present invention;

FIG. 2 is a cross sectioned end view of the nozzle taken substantiallyalong line 2-2 of FIG. 1;

FIG. 3 is an end view of the nozzle as viewed substantially along line33 of FIG. 1;

FIG. 4 is a cross sectioned side elevation view of another embodiment offoam generating nozzle constructed in accordance with the principles ofthe invention; and

FIG. 5 is a cross sectioned end view of the nozzle shown in FIG. 4 takensubstantially along line 55 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring particularly to FIGS.1-3, a first preferred embodiment of nozzle constructed and whichoperates in accordance with the principles of the invention comprises anelongate nozzle body 10 having an elongate passage, generally 12,extending therethrough. Passage 12 comprises a first passage section 14adjacent one end 16 of the body and a second passage section 18 adjacentthe other end 20 to the body. Passage section 18 is axially spaced fromthe first section 16 and has a cross sectional dimension smaller thanthat of the first section. The first and second passage sections 14 and18 are axially separated from each other by an annular shoulder 22having a surface 23 which is inclined toward the passage axis a and end20 of the nozzle body as shown in FIG. 1. This shoulder 22 will befurther described in detail hereafter.

End 16 of the nozzle body 10 is stepped to define an annular surface 24which lies in a plane substantially perpendicular to the axis a of thepassage. A circular orifice plate or disc 26 is positioned againstannular shoulder 24 and held in position by a lip 28 which is crimpedover the other side of the plate as shown in FIG. 1. A plurality of fineorifices 29 and 30 are drilled through the plate 26. The axes of theorifices 29 and 30 are spaced from each other and are radially spacedfrom the axis a of the passage 12. Preferably the axes of the orifices29 and 30 extend in a direction parallel to the axis a such that liquidfoam producing agent which is jetted through these orifices is alsojetted along paths substantially parallel to the axis of the passage andcoincident with the axes of the orifices and impinge on surface 23, thejets J being shown in FIG. 1.

The end 16 of the nozzle body is also threaded at 32 to receive asuitable coupling (not shown) which couples the nozzle body with asupply of a suitable liquid foam producing agent. In the alternative,the nozzle body may be positioned in a suitable nozzle cap (not shown)which, in turn, is coupled to a supply of foam producing agent.

A plurality of air inlet apertures 33 and 34 are also bored radiallythrough the nozzle body and into passage section 14 for introducing airinto the passage 12, preferably by way of aspiration. The liquidorifices 29 and 30 and air inlet orifices 33 and 34 preferably areoffset relative to each other such that the jets J pass between adjacentones of the air inlet orifices. This arrangement avoids the possibilityof liquid droplets building up in the air orifices which might disturbthe flow of air through the orifices 33 and 34 and drip from theorifices to the exterior of the nozzle body.

The other end 20 of the nozzle body 10 is formed with a suitabledischarge opening 36 for exit of the foam F which is generated inpassage 12. This opening, for example, may take the form of a slottedaperture which will eject the foam in a fanshape. The shape of theopening 36 may be varied depending upon the shape of discharge desired.

Having considered the above description, it is believed that theoperation of the foam generating nozzle shown in FIGS. 1-3 will beevident. However, for purposes of clarity, the operation of thisembodiment of invention will be briefly described.

A source of foam generating agent, such as Fomex, obtainable fromColloidal Products Corporation, Petaluma, California, is coupled to end16 of the nozzle body 10 and this foaming agent is fed to the plate 26under a pressure of about 40 psig. Such foam producing agents may, andusually, include commercial foaming agents as diluted with a suitableamount of water or other diluents. In fact, the term foam producingagent as referred to herein may include water only as it has been foundthat the invention will operate reasonably well with water to which noother commercial foaming materials have been added.

As the foaming agent passes through orifices 29 and 30, a plurality ofdiscrete fine jets J are formed. These jets J are jetted past the gasinlet apertures 33 and 34 in an axial path which is substantiallyparallel to axis a and the jets impinge the solid inclined surface 23 ofshoulder 22 which lies in their axial path. The jets J upon impingementare deflected toward the axis a of the passage where the deflectedliquid foam producing agent is thoroughly and intimately mixed in thereduced passage section 18 with the air'which has been aspirated throughorifices 33 and 34. The air is aspirated into the passage due to thereduced pressure which is created in passage section 14 due to thepresence of the high speed liquid jets J passing the air orifices 33 and34. The intimate mixing of th deflected liquid foam producing agent andair in passage section 18 produces a high quality foam which is thendischarged from the slotted discharge opening.

Referring to FIGS. 4 and 5, a second embodiment of foam generatingnozzle and method is shown in which a pintle is positioned in the nozzlebody passage to enhance the generation of foam.

In this embodiment the elongate nozzle body 50 includes a passage 52extending through the body. One end 54 of body 50 is externally threadedat 56 to receive a coupling for coupling the body to a suitable supply(not shown) of liquid foam producing agent under pressure. The passage52 is also internally threaded at 58 adjacent end 54 to receive athreaded bushing 60 having a fluid inlet passage 62 extendingtherethrough.

A pintle 68 includes a pair of discs 70 and 71 which are spaced axiallyfrom each other along passage 52 by a rod 72 to which they are firmlyaffixed. Disc 70 is substantially the same diameter as passage 52 anddisc 70 is clamped between the internal end 74 of bushing 60 and anannular step located on the passage wall to properly position the pintle68 in the passage 52. The downstream disc 71 is preferably smaller indiameter than disc 70 to allow the foam to freely flow between its edgesand the wall of passage 52.

The shoulder 80 abruptly terminates upstream of a plurality of air inletorifices 82 which are bored radially through the body 50 for introducingair into passage 52.

A plurality of orifices 84 are also bored axially through the thicknessof disc 70. These orifices 84 will form fine jets J on the foamproducing agent which aspirate air through orifices 82 and will impingethe upstream face 86 of disc 71 as shown in FIG. 4.

A foam discharge opening is located at the other end 88 of the body 50.This opening may also take the form of a slot 90 formed in a threadednozzle tip 92 which is threaded onto threads 94 on the body 50.

The operation of the foam generating nozzle shown in FIGS. 4 and 5 is asfollows:

The liquid foam producing agent is supplied under pressure to the end 54of nozzle body 50. This liquid flows through passage 62 in bushing 60and through the axial orifices 84 to form the discrete thin axiallydirected jets of liquid J. Upon leaving orifices 84, jets J will createa pressure drop as they pass orifices 82 to aspirate air into passage52. As jets J further move downstream they will impinge the surface 86of disc 71 producing turbulence and intimate mixing with the air whichhas been aspirated into passage 52 to enhance the quality of the foam.The foam thus generated will leave disc 71 and exit from the dischargeslot 90.

Although the orifices 82 and 84 are shown in registry with each other inFIGS. 4 and 5, it will be understood that they may be offset from eachother for the reasons set forth with respect to the embodiment shown inFIGS. 1-3.

It will also be understood that although the foam generating nozzlesdescribed herein are shown having pairs of liquid and air orifices, thenumber of orifices may be varied without departing from the spirit andscope of the invention. Moreover, it is not intended that the foamgenerating nozzles and methods of the present invention be construed asbeing limited to use in agricultural applications only, but are intendedto be useful in the generation of foam of widely varying characteristicsand uses.

In addition, it will be understood that numerous modifications may bemade by those skilled in the art without departing from the true spiritand scope of the invention, the above described embodiments of thepresent invention being merely illustrative of a few of the applicationsof the principles of the invention.

What is claimed is:

l. A foam generating nozzle comprising,

a nozzle body having an elongate passage extending through the majorpart of the length of said body,

a liquid inlet at one end of said body for introducing a liquid foamproducing agent to said passage,

orifice means adjacent said one end of said body, said orifice meanshaving an axis and forming at least one discrete jet of liquid foamproducing agent in said passage along said axis when said agent isintroduced through said liquid inlet,

gas inlet means on said nozzle body between said orifice means and theother end of said body for introducing a gas into said passage,

a solid impingement surface in said passage between said orifice meansand the other end of said body positioned in the path of said jet onsaid axis, said surface deflecting said jet which impinges thereontoward the axis of said passage to effect intimate mixing of the liquidfoam producing agent and the gas to generate foam in said passage, and

foam discharge means adjacent said other end of said body, said passagebeing of substantially constant cross section over its length betweensaid solid impingement surface and said foam discharge means.

2. The nozzle of claim 1 wherein said passage extends axially betweenthe ends of said body.

3. I h e nozzle of claim 1 wherein said orifice means comprises aplurality of orifices spaced radially from the axis of said elongatepassage, said orifices forming a plurality of fine jets each of whichimpinge said solid impingement surface.

4. The nozzle of claim 3 wherein said gas inlet means also comprises aplurality of orifices through said body.

5. The nozzle of claim 4 wherein said gas inlet orifices are positionedbetween said plurality of liquid orifices and said solid impingementsurface and said liquid foam producing agent orifices are offset fromeach other such that each of said jets pass between adjacent ones ofsaid gas inlet orifices.

6. The nozzle of claim 1 wherein said orifices means comprise a platepositioned at said one end of said passage, said plate having aplurality of orifices therein radially spaced from the axis of saidelongate passage.

7. The nozzle of claim 1 wherein said orifice means directs said jet ina path substantially parallel to the axis of said passage.

8. The nozzle of claim 1 wherein said orifice means and said gas inletmeans are positioned relative to each other such that the jet issuingfrom said orifice means reduces the pressure in said passage adjacentsaid gas inlet means to a pressure below atmospheric pressure, wherebythe gas is aspirated into said passage through said gas inlet means.

9. The nozzle of claim 1 wherein said solid impingement surfacecomprises a shoulder defined on said body in said passage, said shoulderbeing positioned in the path of said jet.

10. The nozzle of claim 9 wherein said shoulder is annular.

11. The nozzle of claim 9 wherein said shoulder is sloped toward saidfoam discharge means whereby said jet is deflected toward the axis ofsaid passage.

12. The nozzle of claim 9 wherein said passage comprises a first sectionand a second section axially downstream from said first section, saidsecond section having a cross section smaller than said first sectionand being separated from said first section by said shoulder.

13. The nozzle of claim 1 wherein said foam discharge means conprises aslotted opening.

14. The nozzle of claim 1 wherein said gas inlet means is axiallypositioned between said orifice means and said solid impingementsurface.

15. A method of generating foam comprising the steps of:

forming at least one discrete jet of a liquid foam producing agent in afoam generating passage along an axial path,

impinging said jet upon a solid surface in said axial path of said jetin said passage, introducing a gas into said passage downstream of thelocation at which said fine jet is formed,

intimately mixing said gas and the liquid foam producing agent deflectedfrom said solid surface together to generate foam in a portion of saidpassage having substantially constant cross section over its length, and

discharging said foam from said portion of said passage.

16. The method of claim 15 including forming a pluraltiy of said jets ofsaid liquid foam producing agent and directing said jets along a pathsubstantially parallel to and radially spaced from the axis of saidpassage, each of said jets impinging upon said surface.

17. The method of claim 16 wherein said jets impinge upon an annularsurface in said passage.

18. The method of claim 15 wherein said jet is deflected toward the axisof said passage by impingement upon said solid surface.

19. The method of claim 15 wherein said gas is introduced into saidpassage upstream of said solid surface.

20. The method of claim 15 wherein said solid surface includes a disc insaid passage downstream of the location at which said gas is introducedinto the passage.

1. A foam generating nozzle comprising, a nozzle body having an elongatepassage extending through the major part of the length of said body, aliquid inlet at one end of said body for introducing a liquid foamproducing agent to said passage, orifice means adjacent said one end ofsaid body, said orifice means having an axis and forming at least onediscrete jet of liquid foam producing agent in said passage along saidaxis when said agent is introduced through said liquid inlet, gas inletmeans on said nozzle body between said orifice means and the other endof said body for introducing a gas into said passage, a solidimpingement surface in said passage between said orifice means and theother end of said body positioned in the path of said jet on said axis,said surface deflecting said jet which impinges thereon toward the axisof said passage to effect intimate mixing of the liquid foam producingagent and the gas to generate foam in said passage, and foam dischargemeans adjacent said other end of said body, said passage being ofsubstantially constant cross section over its length between said solidimpingement surface and said foam discharge means.
 2. The nozzle ofclaim 1 wherein said passage extends axially between the ends of saidbody.
 3. The nozzle of claim 1 wherein saeid orifice means comprises aplurality of orifices spaced radially from the axis of said elongatepassage, said orifices forming a plurality of fine jets each of whichimpinge said solid impingement surface.
 4. The nozzle of claim 3 whereinsaid gas inlet means also comprises a plurality of orifices through saidbody.
 5. The nozzle of claim 4 wherein said gas inlet orifices arepositioned between said plurality of liquid orifices and said solidimpingement surface and said liquid foam producing agent orifices areoffset from each other such that each of said jets pass between adjacentones of said gas inlet orifices.
 6. The nozzle of claim 1 wherein saidorifices means comprise a plate positioned at said one end of saidpassage, said plate having a plurality of orifices therein radiallyspaced from the axis of said elongate passage.
 7. The nozzle of claim 1wherein said orifice means directs said jet in a path substantiallyparallel to the axis of said passage.
 8. The nozzle of claim 1 whereinsaid orifice means and said gas inlet means are positioned relative toeach other such that the jet issuing from said orifice means reduces thepressure in said passage adjacent said gas inlet means to a pressurebelow atmospheric pressure, whereby the gas is aspirated into saidpassage through said gas inlet means.
 9. The nozzle of claim 1 whereinsaid solid impingement surface comprises a shoulder defined on said bodyin said passage, said shoulder being positioned in the path of said jet.10. The nozzle of claim 9 wherein said shoulder is annular.
 11. Thenozzle of claim 9 wherein said shoulder is sloped toward said foamdischarge means whereby said jet is deflected toward the axis of saidpassage.
 12. The nozzle of claim 9 wherein said passage comprises afirst section and a second section axially downstream from said firstsection, said second section having a cross section smaller than saidfirst section and being separated from said first section by saidshoulder.
 13. The nozzle of claim 1 wherein said foam discharge meansconprises a slotted opening.
 14. The nozzle of claim 1 wherein said gasinlet means is axially positioned between said orifice means and saidsolid impingement surface.
 15. A method of generating foam comprisingthe steps of: forming at least one discrete jet of a liquid foamproducing agent in a foam generating passage along an axial path,impinging said jet upon a solid surface in said axial path of said jetin said passage, introducing a gas into said passage downstream of thelocation at which said fine jet is formed, intimately mixing said gasand the liquid foam producing agent deflected from said solid surfacetogether to generate foam in a portion of said passage havingsubstantially constant cross section over its length, and dischargingsaid foam from said portion of said passage.
 16. The method of claim 15including forming a pluraltiy of said jets of said liquid foam producingagent and directing said jets along a path substantially parallel to andradially spaced from the axis of said passage, each of said jetsimpinging upon said surface.
 17. The method of claim 16 wherein saidjets impinge upon an annular surface in said passage.
 18. The method ofclaim 15 wherein said jet is deflected toward the axis of said passageby impingement upon said solid surface.
 19. The method of claim 15wherein said gas is introduced into said passage upstream of said solidsurface.
 20. The method of claim 15 wherein said solid surface includesa disc in said passage downstream of the location at which said gas isintroduced into the passage.